1. Field of the Invention
The present invention generally relates to tools used to handle or bond thin filaments, and more particularly to a tool used to form a plurality of discrete optical fibers into a ribbon format.
2. Description of the Prior Art
In recent years, fiber optic cables have replaced traditional copper wire as the preferred medium for telecommunications. As with copper wires, it is often necessary to splice optical fibers together, either for new installations, or for the repair or replacement of existing cables. The present invention relates to a tool used in such splicing operations.
In the past nearly all optical fibers were packaged in discrete form, i.e., a fiber optic cable typically included four to twelve fibers loosely bundled in a buffer tube. When the fibers were to be spliced with another set from a different cable, it was necessary to separately splice each fiber, either mechanically or by fusion splicing. Today, optical fibers are often constructed in a ribbon format, usually consisting of two to twelve fibers bonded together and lying in a common plane. The provision of such fiber ribbons simplifies the splicing operation, since all fibers may simultaneously be stripped, cleaved and spliced to another ribbon. See, e.g., the multiple optical fiber mechanical splicing system disclosed in U.S. patent application Ser. No. 07/753,333, assigned to Minnesota Mining and Manufacturing Co. (3M-assignee of the present invention).
As fiber ribbons and related splicing systems become more widely deployed, it becomes more desirable to be able to easily and quickly transform a bundle of discrete fibers into a ribbon format, for two reasons. First, when the fibers are formed into a ribbon, they can be more economically spliced en masse. Secondly, when it is necessary to splice a plurality of pre-existing discrete fibers to a new fiber ribbon, it is preferable to make the discrete fibers compatible with the ribbon format to take advantage of the economies of mass splicing, rather than separating out the fiber ribbon into individual fibers and making several discrete splices. The latter approach is very time consuming, and results in a large volume of splice bodies which add cost and crowd splice trays which keep the fibers organized.
In the construction of fiber ribbons, a bonding layer such as adhesive tape may be used to join the individual fibers after they are buffer coated and prior to placement in a lightguide cable. For example, the ASR fiber ribbon sold by American Telephone & Telegraph (ASR is a trademark of AT&T), uses a polyester-backed adhesive tape. This technique is, however, highly unsuited for field ribbon construction operations, as the machinery was developed for factory manufacturing.
One technique which may be used in the field involves the direct application of an adhesive material to the optical fibers, such as is used in the multi-fiber arrangement tool of Alcoa-Fujikura Ltd. This procedure is still inadequate, however, since the adhesive is difficult to apply in a uniform coating, and the resulting ribbon often has gaps between the fibers, and the fibers may not be completely bonded together, rendering them unsuitable for the splicing operation. It would, therefore, be desirable and advantageous to devise a tool which would simplify the bonding together of a plurality of optical fibers into a ribbon format, to facilitate mass splicing of the fibers. The tool should ensure that the fibers are positioned uniformly with no gaps, that they remain undamaged, that they are adequately bonded together, and that the resulting ribbon has a uniform width with no overhanging edges of tape.